#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
//void fun(int a = 0)
//{
//	cout << a << endl;
//}
//int main()
//{
//	fun(1);
//	fun();
//}

void fun(int a, int b = 0, int c = 0)
//void fun(int a = 0, int b, int c = 0)
{
	cout << "a=" << a << endl;
	cout << "b=" << b << endl;
	cout << "c=" << c << endl;
}
int main()
{
	fun(1, 2, 3);
	fun(1, 2);
	fun(1);
	//fun(,2,);
	return 0;
}